Increasingly stringent regulations and public demand for improved purification of water supplies have highlighted the need for improved water treatment technologies. Removal of certain organic substances to extremely low levels for drinking water treatment is required by the Safe Drinking Water Act 1986 Amendments. These include volatile organic chemicals (VOCs), synthetic organic chemicals (SOCs), and a wide range of disinfectant byproducts (DBPs). The maximum contaminant level for benzene, for example, is 5 Mg/l. Similarly, treatment of contaminated groundwaters and certain wastewater streams must attain extremely low levels of such organic compounds.
Current technologies available for attaining low concentrations of impurities remain expensive. One aspect of such treatment which generally increases the cost is the interference of other organics in the water, which may be present in concentrations equal to or greater than the organic substance to be removed. In natural surface or groundwaters, such interfering organics are often breakdown products of living organisms, including humic or fulvic materials. Particularly when using adsorption processes, such as those employing activated carbon, these organics are readily removed from the aqueous phase. Although these organics may be relatively harmless in many cases, they consume much of the removal capacity of these removal of the targeted organic. A need therefore exists for a process for the preferential removal of organic contaminants such as VOCs, SOCs, DBPs, and other lower molecular weight, relatively hydrophobic organics in the presence of similar or greater concentrations of organic constituents with greater molecular weight or size such as natural organic matter. In addition, the process should use components which can be chemically regenerated and reused, while the removed organics are separated for reuse or disposal.